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Coupe Suspension Settings - help!
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Author:  MiniMike [ Tue Sep 11, 2012 5:53 am ]
Post subject:  Coupe Suspension Settings - help!
I want to take the Coupe in and have a 4 wheel alignment done as the car seems quite twitchy when hitting bumps in the road, and not as stable as I would like at higher speeds. I have read all sorts of threads on here on setting up the suspension, but can't seem to find a 'standard' set of values to give the shop. I am running 185/60R13 tires on 13 inch rims, 8.4 discs. Front is 5.5inches and rear is 6.0 inches from ground to the bottom of the sill. The front and rear have has the GTM modified lower arms which I think are the -1.5 degree arms, standard tie bars with poly front mounts. Rear has spaced drums and the GTM steering lock with two tie rod ends and adjustable hex bar. So as a good starting point what should set up to.....

Front
Camber - fixed at -1.5
Caster - 3.0?
Toe in - 2.0 mm?

Rear
Camber - fixed at -1.5
Caster - 2.0?
Toe in - 2.0mm?

Or other suggestions????

The shop I use does lot's of minis and the owner has several, and he does a good job on my VTEC sedan.. but I want to try and give him some guidance for the GTM.. I don't know a lot about the suspension setup myself, so any help appreciated..Thanks
Author:  minitici [ Tue Sep 11, 2012 9:52 am ]
Post subject:  Re: Coupe Suspension Settings - help!
Unless you have adjustable tie rods, I don't see you being able to vary the caster.
Caster is normally expressed in degrees.
At the front the caster is usually about 3 to 5 degrees (top pivot rearwards of the bottom pivot).
At the rear you should try for zero caster.

-1.5 degrees camber is about right for a starting point.

I like a bit of toe-in at the front and rear. About 3mm (1/8") total toe-in is a good starting point.

For ride height the car should also pitch down towards the front by about 1".
Author:  West [ Tue Sep 11, 2012 10:46 am ]
Post subject:  Re: Coupe Suspension Settings - help!
As above really

1.5 degrees negative camber all round

2mm toe in all round measured at the wheel rim [13 inch] is a good starting point. Do not put toe out on the rear. Parrellel on the rear can be alot of Fun but I suggest starting with toe in get a feel for the car and if you want it a bit more lively start removing some toe on the rear.

5 degrees of castor

18-20 psi front 22-24 psi rear are good starting points

1 inch of rake measured between the front and rear of the seal.

Make sure your hilos if fitted are near the same settings ideally corner weighted. and the car is settled before setting up.

Neil
Author:  MiniMike [ Tue Sep 11, 2012 3:54 pm ]
Post subject:  Re: Coupe Suspension Settings - help!
Thanks, that gives me a good starting point. I have one set of adjustable tie bars, which I can fit at one end or the other if required. I don't race the car, but use will use it for more daily driving and longer highway trips so looking mostly for stability on the highway and over bumps!

"1 inch of rake measured between the front and rear of the seal." Not sure where you are measuring here West , I was measuring right on the bottom edge of the side sills, at the farthest edges.. ie right behind the front tire, and just in front of the rear tire.
Author:  West [ Tue Sep 11, 2012 7:20 pm ]
Post subject:  Re: Coupe Suspension Settings - help!
MiniMike wrote:
"1 inch of rake measured between the front and rear of the seal." Not sure where you are measuring here West , I was measuring right on the bottom edge of the side sills, at the farthest edges.. ie right behind the front tire, and just in front of the rear tire.



Yes your measurements are correct right at each end of the side sill... my mistake I was doing two things at once and wrote the wrong word. :roll: Mind and fingers doing slightly different things. :lol:

Neil
Author:  MiniMike [ Tue Sep 11, 2012 8:07 pm ]
Post subject:  Re: Coupe Suspension Settings - help!
OK, thought you might have had some ocean seals hanging around the car!
Author:  turbocox [ Tue Sep 11, 2012 10:02 pm ]
Post subject:  Re: Coupe Suspension Settings - help!
Coupe Suspension Settings - help!

You also need this set up, as I notice you have the old one.

If you kneel down looking at the rear wheel, put your hands at the quater to three position, start pushing with one hand and pulling with the other, and alternating between the two (pushing and pulling).
You will notice that there is movement . "Twitchy" (toe in then toe out)

This set up eliminates this.



Image


rossabitz wrote:

Rossabitz.
The locking kit is £230+vat+postage.
It bolts on to Mini or Metro hubs without modifying any standard parts.
Female rod ends can be used with the original GTM track rod as shown
or male ends used with a tie bar from Mcgill Motorsport.

_________________
THE WORLD'S FASTEST 'A' SERIES COX GTM 1/4....13.502 @115mph MITP 08
Author:  MiniMike [ Mon Sep 24, 2012 1:05 am ]
Post subject:  Re: Coupe Suspension Settings - help!
Thanks.. tried pulling on the wheels and found some play.. source was the lower arm bushings.. pretty much knackered.. replaced them all with poly ones and set up the rear alignment by string.. much improved handing.. but will take it in now to the shop to have it done with the fancy machine and lasers.. good check on my work! Car is finally running well so have had some great drives this weekend..
Author:  MiniMike [ Wed Sep 26, 2012 3:31 am ]
Post subject:  Re: Coupe Suspension Settings - help!
Well got into the shop today and got the alignment sorted.. handles way better, the back end is behaving nicely. It's pretty quick on the steering, so some getting used to that. Thanks for the feedback on the settings..I had set the rears up myself before taking it in, using the string method and it was almost bang on, but had not done the front, which I found out was quite a ways off..so all good now on the alignment.
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